This invention relates to automobile windows and more particularly to a window regulator or lift mechanism for raising and lowering automobile windows.
In conventional automobile window assemblies of the type where the window is actuated vertically, a seal extends along the upper portion of the window opening and the window seats against this seal in the closed position. Some recent window seal configurations require a significant closing force for the window to properly seat against the seal to form the desired tight-seal engagement.
In electric window assemblies, a greater lifting force can be achieved with a higher capacity motor. However, it is somewhat inefficient and disadvantageous to utilize a larger motor with a higher torque in order to attain a greater window closing force First, a larger motor increases the cost of the assembly Secondly, a larger motor may result in excessive wear. A higher lifting torque is required only over a small section of the window travel path, i.e., from the point where the window initially engages the upper seal to the fully closed position. Therefore, a higher lifting torque during the remainder of the window travel path is unnecessary and can produce unnecessary additional stress and wear on the window lift assembly. Furthermore, there are also potential hazards in using a high lifting torque prior to the very end of the window travel path. In electric windows, there is a danger of injury from being caught in the window especially with respect to small children. For safety considerations, it is desirable that any increased lifting torque be effective only when the window is sufficiently closed so as to inhibit or prevent an accidental catching
In manual window assemblies, there are related considerations of convenience and speed in achieving a greater window closing force. The force required to properly engage the window seal may be troublesome to some people without assistance of an increased mechanical advantage. However, the tradeoff for an increased mechanical advantage is generally speed so that manual window operation may be inconvenient if a higher lifting torque is utilized over a significant portion of the travel path of the window.
Therefore, in both electric and manual window assemblies, it is desirable to achieve a high window closing force only during the latter part of the closing movement of the window as the window engages and seats against the upper window seal. Other applications may benefit from a change in mechanical advantage at other points along the window travel path.
Accordingly, it is an object of the present invention to provide a new and improved window lift mechanism for varying mechanical advantage over predetermined sections of the window travel path.
Another object of the invention is to provide such a window lift mechanism which achieves an increased closing force for the proper engagement of window and seal.
Another object of the invention is to provide such a window lift mechanism which achieves an increased closing force only during the latter part of the window travel path.
A further object of the invention is to provide such a window lift mechanism wherein the transition to an increased closing force is virtually instantaneous, smooth, and quiet.
A further object of the invention is to provide such a window lift mechanism which is suitable for electric and manual drive.
A still further object of the invention is to provide such a window lift mechanism which is cost efficient, adaptable to wide variety of window configurations, and safe, convenient, and durable in operation.
Other objects will be in part obvious and in part pointed out more in detail hereinafter.
Accordingly, it has been found that the foregoing and related objects and advantages are attained in an automobile window lift mechanism having a lift arm assembly, a pinion gear for actuating the lift arm assembly and a gear train interconnecting the pinion gear and the lift arm assembly. The lift arm assembly is configured for raising and lowering a window along a path of travel between an open position and a closed position where the window is in sealing engagement with an upper window seal. The window travel path comprises a first larger section extending between the open position and a predetermined position where the window is adjacent the upper seal and a second smaller section extending between the predetermined position and a closed position where the window is in seal-tight engagement with the upper window seal. The pinion gear supplies rotative force for actuating the lift arm assembly to raise and lower the window and the interconnecting gear train is configured to provide a first mechanical advantage over the first section of the window travel path and a greater second mechanical advantage over the second section of the travel path. The greater second mechanical advantage produces an increased closing force so the window properly seats against the seal.
In one embodiment, the interconnecting gear train includes a gear reduction configuration which provides an increased mechanical advantage only over the second section of the window travel path. In another embodiment, the gear train includes a larger effort arm between the pinion gear and the lift arm assembly for a greater mechanical advantage only during the second section of the window travel path. Other embodiments comprise a gear train which includes the combination of gear reduction and a larger effort arm for achieving a higher lifting torque only during the latter part of the window travel path.